1. Field of the Invention
The present invention relates to a video signal reproducing method and apparatus.
2. Description of the Related Art
Conventionally, a multi-channel segment recording and reproducing method has been known such that video signals for one picture are divided into a plurality of segments and further recorded or reproduced simultaneously through a plurality of channels to obtain recorded or reproduced video signals of wide band.
In the tape pattern of this multi-channel multi-segment recording and reproducing method, since one picture is recorded being divided into a plurality of tracks, when the recorded video signals are reproduced at any given variable speed, there exists such a problem in that video signals for predetermined periods in one picture cannot be reproduced and thereby noise bars are inevitably generated.
To overcome this problem, the same Inventors have already proposed such a video signal recording and reproducing apparatus that video signals (e.g., high vision video signals as one example of high-definition television video signals) divided into two channels and audio signals divided into one channel are recorded and reproduced simultaneously, in Japanese Patent Application No. 5-73067 (not yet published in Japan).
The above-mentioned apparatus will be explained in more detail hereinbelow with reference to FIGS. 1 to 5. In FIG. 1, a pair of audio heads A1 and A2, a pair of video heads WP1 and WP2, and another pair of video heads WQ1 and WQ2 are arranged, respectively around a rotary drum at such angular positions as to be opposed to each other (being spaced 180 degrees apart from each other), that is, so as to provide different azimuth angles. Here, the azimuth angles of the two video heads WP1 and WQ1 are the same, and the azimuth angles of the video heads WP2 and WQ2 are the same. On the other hand, the azimuth angles of the audio heads A1 and A2 are different from those of the video heads WP1, WQ1 and WP2, WQ2, respectively. These magnetic heads are mounted at different mounting heights and at different mounting angles, respectively, as shown in FIG. 2. The widths of these heads are roughly 19 .mu.m, respectively for instance, which is equal to the track width. Further, these heads are mounted in such a way that the lower end edges of the video heads WP1 and WP2 and the upper end edges of the video heads WQ1 and WQ2 are located at the same height. In the following description, the assumption is made that the respective widths of the main tracks, the subsidiary tracks and the audio tracks are all equal to each other, and the widths of these tracks are referred to as a reference track width.
Further, the video heads WP1 and WP2 record or reproduce a first TCI (Time Compressed Integration) signal (described later) related to the first segment; on the other hand, the video heads WQ1 and WQ2 record or reproduce a second TCI signal (described later) related to the second segment.
By the magnetic heads as described above, a tape pattern of 3 tracks per field can be obtained as shown in FIG. 3, in which parentheses represent that each track is recorded by a head enclosed by each of the parentheses.
Here, if the tracks related to the video heads WP1 and WP2 are the main tracks and the tracks related to the video heads WQ1 and WQ2 are the subsidiary tracks, the first TCI signals as shown in FIG. 4A are recorded on the main tracks; on the other hand, the second TCI signals as shown in FIG. 4B are recorded on the subsidiary tracks, respectively. Further, in FIG. 4A, PR of the first TCI signal is a signal obtained by compressing the chrominance signal on the time axis along an odd line, and Y1 of the first TCI signal is a video signal obtained by compressing the luminance signal on the time axis along an odd line. Further, in FIG. 4B, PB of the second TCI signal is a video signal obtained by compressing the chrominance signal on the time axis along an even line, and Y2 of the second TCI signal is a video signal obtained by compressing the luminance signal on the time axis along an even line.
Further, the tape pattern on which line numbers are described is shown in FIG. 5, in which parentheses represent that each track is recorded by a head enclosed by each of the parentheses, respectively. Further, SW represents that a switching signal for securing a margin required for switching of the magnetic head is interposed; V represents that a vertical synchronizing signal for obtaining vertical synchronism is interposed; DA represents that a data signal for representing program contents, time codes, etc. is interposed; and CAL represents that a correction signal for correcting two-track (maine track and subsidiary track) transmission characteristics is interposed, respectively.
When the video signals recorded on a magnetic tape TT as described above are reproduced at variable tape travel speeds, since chrominance signals (color differential signals) PR and PB are recorded being divided into the main tracks and the subsidiary tracks, if these signals are separated several fields away from each other (without being adjacent to each other), there exists a problem in that image color is not natural.
In addition, in variable tape travel speed reproduction, since the video signals cannot be processed (e.g., the processing of chrominance signals PB and PR) for each segment without discriminating to which segment the current reproduced signals belong, signals for discriminating the current segment must be interposed several times in one track, thus causing another problem in that the efficiency of utilizing a magnetic medium is inevitably lowered.
Further, in the case of motion picture, there exists another need of making the reproduced motion picture more smoothly.